Known scroll compressors of this kind include, for instance, what is disclosed in Japanese Unexamined Patent Application Publication No. 2010-203327 (Patent document 1). According to this Patent document 1, an oil inlet is formed in the upper face of at least either of an orbiting scroll lap or a fixed scroll lap; a first oil feed channel linking the opening of this oil inlet and a first compression room and a second oil feed channel linking the opening of the oil inlet and a second compression room are formed in the upper face of the lap where the oil inlet is formed; and outlets of the first oil feed channel and of the second oil feed channel are disposed in positions differing in involute angle from each other of the lap where the oil inlet is formed.
This scroll compressor disclosed in Patent document 1 is claimed to be able to uniformly supply sufficient quantities of oil to both the first compression room formed toward the outer wall of the orbiting scroll lap and the second compression room formed toward the inner wall of the same.
However, as the scroll compressor described in the above-cited Patent document 1 has the scroll lap oil inlet for letting fluid in a back pressure room flow out in the upper face (toward the tooth tip) of the scroll lap, a leak loss at the lap tooth tip increases. Furthermore, as oil feed channels for letting fluid in the back pressure room flow out need to be provided within the scroll lap, it involves another problem that the strength of the lap is adversely affected.
It is not impossible to dispense with oil feed channels or an oil inlet in a scroll lap and thereby to avoid a strength loss by providing a scroll compressor having an asymmetric tooth profile with an oil inlet, such as the one mentioned above, which opens toward a tooth bottom between scroll laps of a back pressure room to flow out into a compression room. However, if this configuration is adopted, in order to make the back pressure of the back pressure room communicate with the target pressure level in the compression room on the external line side and the compression room on the internal line side of the orbiting scroll lap will differ in orbiting angle, only one of the external line side compression room and the internal line side compression room can be enabled to communicate with the back pressure room, posing the problem that the compression room not communicating with the oil inlet cannot receive sufficient oil supply.
In order to address the problem noted above, the present invention is intended to provide a scroll compressor that can avoid oiling shortage without sacrificing the lap strength by supplying oil in a back pressure room to both a compression room on the external line side and a compression room on the internal line side of an orbiting scroll lap.